1. Field of the Invention
The present disclosure relates to an improved pellet marking apparatus of the type adapted to imprint certain desired indicia such as trademarks, trade names, lot numbers, or control numbers, on or around the surface of a multiplicity of pellets or the like as the pellets are transported, by way of a conveyor or the like, adjacent the surface of the printing roller. The improved apparatus is characterized by the provision of a hinged connection linking both the printing roller and the design roller with the ink reservoir. In accordance with the invention, the design roller and printing roller are movable between two positions corresponding to operational and dwell states. In the operational state, the design roller is immersed in the ink reservoir to receive ink therefrom. When the reservoir needs replenishing, the design roller is pivotally moved from immersion in the reservoir to a position in which it does not contact the reservoir. Thus, the hinged connection provides easy access to the reservoir so that it can be filled quickly and easily without necessitating disassembly of any part from the mechanism.
2. Prior Art
Many printing mechanisms that are adapted to transport and print upon a multiplicity of uniformly shaped and sized objects are known in the art.
One such device is disclosed in U.S. Pat. No. 2,859,689 (Ackley). Other prior art printing mechanisms include those disclosed in U.S. Pat. Nos. 3,868,900 (Ackley); 3,871,295 (Ackley) and 3,931,884 (Ackley).
Basically, in all of the above listed prior art patents, the objects, such as tablets, capsules, pills, and uniformly shaped confectionary products, are transported from a hopper to the printing means by means of an endless conveyor. The printing means usually include a design roller comprising etched portions therein, which etched portions correspond to the desired marking or indicia with which the objects are to be imprinted. The etched portions of the design roller pick up ink from the ink reservoir as the design roller is immersed therein. The design roller contacts a rotatable printing roller so that the ink picked up by the etched portions of the design roller is transferred to the surface of the printing roller.
As the objects pass beneath the printing roller, the desired indicia are imprinted thereon.
In some cases, such as in the printing of capsules which comprise body portions and cap portions of larger diameter than the body portions, it is desirable to "rectify" the capsules prior to their presentment adjacent the printing means. Rectification, as used in the art, refers to a condition in which capsules or objects are all similarly disposed, with the cap portions of all of the capsules extending in one predetermined direction and the body portions extending in another predetermined direction. In this manner, it is possible to uniformly print upon similar portions of each capsule. For instance, a trademark may be imprinted on the same cap portion location of each capsule or the desired indicia may be imprinted only on body portions or on specific loci of both the cap portions and body portions alike.
Also, many of the prior art printing devices are capable of effecting "wrap around" type printing whereby the objects are spun about their axes as they contact the printing roller. Accordingly, in this manner, printing about the circumference or a portion thereof of the objects may readily be effected. In wrap around printing operations, the surface speed of the printing roller is adjusted so that it exceeds the speed of the conveyor that presents the objects thereto. Accordingly, as the printing roller contacts the advancing objects, the objects are spun about their longitudinal axes. To aid in spinning movement of the objects, specially designed pocket members, designed to receive the objects therein, are carried by the conveyor. These pocket members themselves are the subject of our co-pending application, Ser. No. 859,303, filed Dec. 12, 1977.
These prior art printing devices are not without disadvantages, however. In all of the devices, the location of the ink reservoir on the frame makes it relatively inaccessible and when the reservoir needs replenishment, various members, such as the design roll itself, must be removed from the mechanism to permit access to the reservoir. Not only does the step of physically removing certain parts from the mechanism result in lengthy interruption of the printing process, but the parts when replaced after replenishment must be precisely adjusted so that the design roll and printing roller cooperate to properly imprint the desired indicia on the desired portion or portions of the pellet or the like. The proper alignment between the design and printing rolls is critical since, during the printing process, the ink is transferred from the design roller to the printing roller and then to the objects as they pass beneath the printing roller. Thus, after replenishment, if the design roller is not repositioned in exact alignment with respect to the printing roller and the objects, the desired printing will not appear on corresponding portions of the objects. This condition is completely unacceptable commercially and results in substantial economic loss.
Accordingly, there is a great need in the art for a device which will permit ready access to the ink reservoir for easy replenishment thereof, without requiring disassembly of any parts from the mechanism.
Further, despite the advantages afforded by these prior art devices, there remains a need for means for providing precise adjustment of the alignment between the design and printing rollers while both of these members are journalled in the frame.
A mechanism which can provide this adjustment while the machine is running is even more desirable.
Also, the operation of the prior art devices may be, in some respects, dangerous for the operator since sharp edged doctor blades wipe excess ink from the design roll and since the mechanism in general and specifically the nip between the design roll and printing roll are capable of injuring a finger or the like that is carelessly placed therein.
Accordingly, it is an object of the present invention to provide an improved printing mechanism wherein replenishment of the ink reservoir is relatively easy and does not require the disassembly of any part whatsoever from the mechanism.
It is another object of the present invention to provide a means for adjusting the alignment between the design and print rollers.
It is an even more specific object of the present invention to provide a means for adjustably aligning the design roller longitudinally with respect to the printing roll that does not require the machine to be shut down while adjustment is effected.
Further, it is another object to provide varied safety devices that protect the operator from sharp edges of certain components and the nip between the design and printing rollers, which mechanisms can shut down the printing drive altogether when actuated.
These and other objects are met by the improved printer disclosed herein. The construction of the improved apparatus will become apparent in the following description and in the drawings.